MONTPELIER — Three of the candidates seeking to become the next leader of the Vermont National Guard each have decades of military service. The fourth isn’t a guard member and is running primarily to oppose the possibility the Air Force could station F-35s, the next generation fighter planes, at the Burlington International Airport.

The next adjutant general will be chosen Thursday by a joint session of the Legislature.

Lawmakers will cast secret ballots to elect the officer who will lead about 3,000 members of the Army Guard and 1,000 members of the Air National Guard.

The candidates are seeking to succeed Maj. Gen. Thomas Drew, who became interim adjutant general last summer after his predecessor left to become deputy commander of the United States Northern Command, which oversees North American defense. Drew did not seek re-election to the four-year post.

Like much of the U.S. military, the Vermont National Guard is winding down after more than a decade of war. Army and Air Guard members have served numerous overseas deployments, including many that involved sustained combat operations in Iraq and Afghanistan.

But the end of the wars presents its own set of challenges, including caring for the soldiers and airmen after their deployments.

Air Guard Brig. Gen. Steven Cray, of Essex Junction, a veteran F-16 pilot, said he feels the biggest issue facing the guard stems from the fiscal challenges facing the United States and Vermont.

“We’ve already seen that type of pressure from the Air Force being applied to the Air National Guard, and we expect the same to happen on the Army side in the next couple of years,” he said after announcing his candidacy in December.

Guard Col. Darryl Ducharme, a veteran helicopter pilot and guard trainer who has also served in Iraq and Afghanistan, said Tuesday that deployments over the last decade have left up to 20 percent of Vermont guard members with medical conditions that would prevent them from being deployed again.

“I think it’s critical that we get those folks back in a healthy, deployable status,” Ducharme said.

Retired Army Guard Col. Michael Bullock has worked for the guard as a civilian for several years since retiring from uniformed service. He said he served in the Special Forces before joining the Vermont guard, where he was twice deployed to Afghanistan.

He’d like to change the culture of the guard to make it more open to new ideas.

“Our resilience is our people and our ability to work together and come together and get our strength from our diversity,” Bullock said.

James Marc Leas, a lawyer from South Burlington, is the non-guard candidate.

“I think Vermont needs an adjutant general who will serve and protect Vermont with no responsibility to the chain of command in Washington,” Leas said. He cited what he called “unjust wars of aggression” as indicative of the need for independent thinking at the state level.

But Leas’ biggest issue is the possibility the Air Force will station the next generation fighter plane, the F-35, at the Vermont Air National Guard. A decision from the Air Force on that issue is expected this spring.

Opponents of the F-35 plan in communities surrounding Burlington International Airport, where the planes would be based, argue they are much louder than the F-16s they would replace and would affect the quality of life of people who live near the airport.

Proponents say the planes aren’t as loud as critics maintain and would fly only for a few minutes a day a few days a week.